BTW BRAS timeouts?

I remember ISPs using BTW broadband circuits giving the advice that a router should be powered off for 30 minutes to ensure the session expires on the BRAS.

Is this still correct as I've had cause to ask people I'm supporting who are working from home to attempt a router restart and I've been advising them to power off for two minutes but wondered if this was enough?

All router should be powered off for 30 minutes to avoid DLM trigger the line. For Bras IP Profile - wait for 30 minutes when powered off the same way to avoid DLM trigger. Most ISP will updated IP Profile on their system by doing soft disconnected - PPPoE connection only.

Edited by adslmax (Sat 17-Oct-20 15:24:13)

No.
It isn't necessary at all.
In fact I've never seen that advice given to do this unless it gets stuck

Only if you have issues with a stuck profile should you need to leave the PPP session down for an extended period to fix this.

I spent over 8 years using FTTC with probably 100± resyncs in that time. Not once did i wait between resyncs or PPP reconnecting. Not once have i had an incorrect IP profile or a stuck session.

The only similar advise I've seen is when doing something that involves multiple resyncs then it's good practice to leave 30 minutes between taking the dsl offline and reconnecting it.
That's so the DLM ignores the resyncs and nothing to do with stuck sessions.

That's good to know, I have still been advising the 30mins too .

So really it's only if the line and has been on and off, several times in quick succession, ie, your customer has been trying to get it to sync to a higher speed the whole morning and wonders why it is getting slower, basically.

Is that right?

Pretty much.
DLM won't take any action on a line that resyncs once or twice.

If you have ongoing work in the house which involves the power going on and off and the line resyncs 10 times it is likely to be banded by the DLM.
The same goes for swapping modems or tweaking modem settings that cause it to reboot.

The DLM monitors lines using 15 minutes bins. A line losing sync and then syncing again within the same 15 minute bin counts as a strike against the line and is seen as instability.

Modems can send a "Dying gasp" to tell the other side "this resync/power down was intentional and isn't instability " but the DLM ignores dying gasps.

I only advise leaving 30 minutes between taking sync down and bringing sync back up if you intend on doing this multiple times.
1 or 2 resyncs never results in action being taken.

How many resyncs are permitted depends on the DLM policy your ISP uses.

A (fairly) recent ISP briefing from OpenReach informed them of MTBR changes (Mean time between resyncs) for some of the DLM policies.
I believe this reduced the daily allowed count for a line to be treated as "good" from 10 to 5 resyncs, though I'd need to double check that.

As above it isn't necessary for a single resync or even a couple resyncs.

It shouldn't be necessary at all for the IP profile to update correctly.

Edited by j0hn83 (Sun 18-Oct-20 13:21:45)

Cheers John

In reply to a post by j0hn83:

I only advise leaving 30 minutes between taking sync down and bringing sync back up if you intend on doing this multiple times.
1 or 2 resyncs never results in action being taken.

It's happen to me in 2018, power cut has spiked 20 times caused my line banded by DLM next day. After 64 days still stuck on banded, PN request DLM reset to BTw OR to resetted my line.

Edited by adslmax (Sun 18-Oct-20 13:53:31)

In reply to a post by j0hn83:

Modems can send a "Dying gasp" to tell the other side "this resync/power down was intentional and isn't instability " but the DLM ignores dying gasps.

Is there any good reason for that, or did OR just not bother to include it in the software?

Powered down 30 minutes: Swapped PN Hub One fetched sync stats, powered down 30 minutes, swapped Netgear DGND3700v1 fetched sync stats, powered down for 30 minutes, swapped TP Link VR2600 fetched sync stats, powered down for 30 minutes. swapped Billion 8800NL fetched sync stats and finally powered down for 30 minutes swapped Zyxel XMG3927-B50A fetched sync stats. Five times powered down for 30 minutes in a space of 6 hours didn't caused DLM action next day. (that's was few years ago)

All those 30-minute tea breaks, 😂🤣😂🤣😂🤣

Edited by TrevorSP (Sun 18-Oct-20 14:07:52)